Nail machine



July 3, 1934-. C 1,964,988

NAIL MACHINE Filed March 31, 1931 2 Sheets-Sheet l I NV EN TOR.

671a z /es fiff/H/ OT QDZVM. v 5

Patented July 3, 1934 UNITED STATES NAIL MACHINE Charles K. Hill,

Application March 31,

3 Claims.

The present invention relates to a machine for making nails from twistedwire stock, the machine being particularly adapted to handle this stockand to make nails therefrom having a twisted shank.

In the making of nails of the type known as drive screws, i. e., thosehaving a threaded shank, it has been necessary heretofore, first to formthe nail and then to thread the shank of each individual nail aftermanufacture. It is obvious that such a method is costly and slow and theuse of such nails, while desirable due to their great holding power, hasbeen limited by the cost of manufacture. Also, it has been impossible touse certain hard and tough steels for these nails because the dies usedto impart the thread to the nail are quickly worn out on the hard steel.For these reasons it is highly desirable to prepare nails of the type ofdrive screws from a twisted stock rather than from straight stock whichmust be rolled after the nail is formed. However, wire of appreciablelength, such as a roll of wire, has not heretofore been successfullytwisted since such a wiretends to untwist as formed in methods so farattempted.

In my copending application Serial No. 513,262, filed February 4, 1931,there has been described an apparatus and method for twisting wire ofappreciable length and placing it in condition suitable for formingnails therefrom. In

the present application, there is described a machine adapted to takethis twisted wire and make a finished nail therefrom, the nail having athreaded shank. It is, accordingly, an object of this invention toprovide a machine for forming nails automatically and continuously fromtwisted wire. Another object of the invention is to provide a machinewhich may be adjusted to produce nails of different lengths as desired,the

nails produced being accurately formed of uniform length.

To the accomplishment of the foregoing and related ends, said invention,then, consists of the means hereinafter fully described and particularlypointed out in the claims. The annexed drawings and the followingdescription set forth in detail certain mechanism embodying theinvention, such disclosed means constituting, however, but one ofvarious mechanical forms in which the principle of the invention may beused.

In said annexed drawings:

Fig. 1 is a plan view of the nail machine; Fig. 2 is a front elevationof a portion of the machine; Fig. 3 is an enlarged longitudinal sectionthrough a wire feeder forming Part of the nail Cleveland, Ohio 1931,Serial No. 526,584 (01. 10-46) machine; Fig. 4 is a transverse sectionthrough the wire feeder taken along the line 4-4 of Fig.

1; Fig. 5 is a perspective view of a piece of twisted wire; Fig. 6 is aperspective of the wire with rounded sections; Fig. 7 is a sectionshowing a nail cut-01f; and Fig. '8 is a perspective. View of a nailformed by the nail machine.

Referring to Fig. 1 of the drawings, a twisted wire from a roll such asis formed in my copending application above referred to, is passedthrough wire straighteners 9 and 11, one of these being verticallyplaced and the other horizontally placed. Each of these straightenershas a plurality of rollers 12 connected by straps 13 between which thewire passes and is straightened. The wire next goes to a sliding plate14 which is caused to reciprocate by the bell crank 15 through the link16. The bell crank is operated by a shaft 17 connected to a wheel 18.

The sliding plate 14, as shown in Figs. 3 and 4, consists of the plate19 having a longitudinal passage 21 through which the wire 22 passes,entering the plate through the bushing 23. A strip of metal 24 liesalongside the wire and rollers 25 contact with this strip. Each rollerlies in an orifice having a lateral wall 10 which slopes toward thestrip 24 thus narrowing the orifice in the direction from which the wireis being fed, the rollers being normally held in the narrow end of theorifice by plungers 26 acted upon by the springs 2'7. The rollers areotherwise unattached and the strip 24 is also unattached, being free tomove laterally a limited distance with respect to the plate 14, that is,radially to the axis of the wire which is fed through this plate. As theplate 14 is drawn back by the bell crank 15 and the link 16, the rollers25 are forced rearwardy against the springs into the wider part of theorifice where they do not bear on the strip and the plate travels backfreely. On the other hand, when the reciprocating plate begins itsforward stroke, the friction of the twisted wire on the strip 24 causesthe latter to lag behind the sliding plate and to draw the rollers downinto the narrow part of the orifices where they exert pressure on thestrip which is transmitted to the wire. In fact, the wire is firmlygripped by the sliding plate and is drawn forward the length of onestroke. In practice a very small clearance exists between the ends ofthe strip 24 and the plate 19, so as to permit sufficient movement ofthe strip longitudinally of the plate to permit the limited radialmovement which has been described. The strip 24 need move radially buttwo or three thousandths of an inch to release the wire, so that thenecessary end clearance for the strip 24 need be of the order of only afew thousandths of an inch.

As the wire comes to rest after being drawn forward this amount, it isstamped by jaws 28 which, as may be seen in Fig. 2, have each a halfround indentation which rounds the twisted wire correspondingly atintervals measured by the length of stroke at which the sliding plate 14is operated. The jaws are mounted in holders 29 and are held therein bythe pieces 31 and the bolts 32. The jaw holders are mounted in guides 33and 34, the lower jaw being slidably mounted.

Intermittent motion is imparted to the lower jaw through the link 35which connects the jaw holder to a lever 36. This lever has a roller 37which contacts with a cam 38. A spring 39 retracts the jaw after thelatter has stamped the wire.

To secure synchronized operation of the slide plate 14 and the jaws 28,both of these elements are operated from the same source. The arm 17which rocks the bell crank 15 is connected, as above mentioned, to thewheel 18 by means of a fork 41 connected to a key 42 which fits in akeyway 43. To regulate-the length of stroke of the slide plate 14, thekey may be set at any desired distance from the center of the wheel 18in the keyway 43 which is cut in the wheel. As this wheel imparts areciprocating motion to the slide plate, it also revolves the cam 38which periodically forces the roller 37 outward and presses the jaws 28together. The wheel 18 and appurtenant parts are supported from theframe of the nail machine by means of the hanger 44.

The twisted wire now leaves the jaws 28 and proceeds through the machinewith accurately spaced rounded portions 45 as best seen in Fig. 6. Aseach rounded portion reaches the grip jaws 46, the wire is cut off atthese rounded portions by the knives 47 and is headed by the hammer 48.This completes the formation of the nail.

The operation of the nail machine in making nails having threaded shanksfrom twisted stock is as follows: The wire passes through thestraighteners 9 and 11 where it has any bends or kinks taken out, thestraightened wire proceeding to the sliding plate 14 where it isperiodically gripped by the rollers 25 and forced through the machine.The slide plate repeatedly moves freely toward the incoming stock, gripsit, and draws it forward an amount approximately equal to the length ofa finished nail. Due to the firm grip with which the sliding plate holdsthe wire, there is no slip and the stock is accurately measured for thefinished nail. As before mentioned, the sliding plate releases its gripon the stock while performing the return stroke and, during thisinterval, the stock remains at rest to be stamped between the jaws 28and given a rounded contour thereby. Since the jaws and the slidingplate are driven from the same means, they may be synchronized so thatthe stamping operation takes place while the stock is at rest, anobvious requirement since the moving stock cannot be stamped.

The twisted wire now has a series of equally spaced rounded sectionsalong its length and proceeds in that form to the gripping jaws 46 whichhold the wire while beveled knives 47 cut the stock at one of therounded sections. This places the point on one nail which is thusfinished and drops into a receiver while, at the same time, providing anend on the succeeding nail which is immediately headed up by the hammer48. These nail-finishing means are of conventional construction andoperation, being timed to form the stock at the rounded portions 45.

Fig. 5 illustrates a piece of the uniformly twisted wire stock fromwhich the nails are made, this stock being originally square in crosssection or of any section other than round. In Fig. 6 is illustrated apiece of stock after rounded sections have been placed thereon atregular intervals by the jaws 28, obliterating the twist at these pointsin order that thenail pointing and heading operations may be performedon the stock. A finished nail having a threaded shank, as produced in myapparatus, is shown in Fig. 8. Such a nail is as readily and cheaplymanufactured by the present method and apparatus as a nail with astraight shank and yet has all the advantages resulting from a threadedshank. Such a nail has great holding power and will break before it canbe withdrawn by a direct pull. This method of making nails permits hardand tough steels to be used since there are no dies to wear out rapidly,the nail formed from such steels, for example manganese steels, beingvery strong and capable of being driven through very hard materialswithout bending.

Other modes of applying the principle of my invention may be employedinstead of the one explained, change being made as regards the mechanismherein disclosed, provided the means stated by any of the followingclaims or the equivalent of such stated means be employed.

I therefore particularly point out and distinctly claim as my invention:

1. An apparatus for making nails having threaded shanks, which comprisesa reciprocably mounted feed member, a passage therethrough for a twistedwire, a flat-faced gripper lying alongside said passage and capable oflimited movement relative to the feed member, inclined surfaces spacedfrom said gripper, and wedging means coacting with said surfaces toforce the gripper into holding relation with the twisted wire whenmoving in one direction and releasing on the other direction.

2. An apparatus for making nails having threaded shanks, which comprisesa reciprocably mounted feed member, a passage therethrough for a twistedwire, a flat-faced gripper lying alongside said passage and capable oflimited movement relative to the feed member, inclined surfaces at theback of said gripper, and multiple rollers coacting with said surfacesto force the gripper into holding relation with the twisted wire whenmoving in one direction and releasing on the other direction.

3. An apparatus for making nails having threaded shanks which comprisesa reciprocably mounted plate, a pasage therethrough for a twisted wire,a flat strip lying alongside said passage, and capable of limitedlateral move- 0 ment relative to said plate, multiple rollers positionedin said plate and bearing against said strip, and inclined surfaces insaid plate adapted to force said rollers against said strip to cause thelatter to grip a wire when the plate is mov- 5 ing in a certaindirection.

CHARLES K. HILL.

